1. Field of the Invention
The present invention generally relates to an array substrate and a repair method, in particular, to a thin film transistor (TFT) array substrate and a repair method.
2. Description of Related Art
In recent years, with great advance in the fabricating technique of electrical-optical and semiconductor devices, flat panel displays (FPDs), such as liquid crystal displays (LCDs), have been developed. Due to the merits of LCDs, for example, low operation voltage, no harmful radiation, light weight, and compact size, LCDs replace the conventional Cathode Ray Tube (CRT) monitors and become the mainstream.
FIG. 1 is a simplified cross-sectional view of a conventional liquid crystal display module. Referring to FIG. 1, the liquid crystal display module 100 comprises a thin film transistor (TFT) array substrate 110, a color filter substrate 120, a sealant 130, a liquid crystal layer 140, polarizing films 152, 154 and an outer frame 160. The sealant 130 is disposed between the color filter substrate 120 and the thin film transistor array substrate 110. The liquid crystal layer 140 is disposed within the space bounded by the color filter substrate 120, the thin film transistor array substrate 110 and the sealant 130. Furthermore, the polarizing films 154, 152 are disposed on other sides of the thin film transistor array substrate 110 and the color filter substrate 120, respectively. The outer frame 160 is disposed on the polarizing film 152. In addition, the thin film transistor array substrate 110 can be divided into a pixel region 110a and a peripheral circuit region 110b, wherein the peripheral circuit region 110b can be divided into an outer area R2 and an inner area R4. The peripheral circuit region 110b has a plurality of lead lines 112 therein for connecting pixels in the pixel region 110a and peripheral circuits for driving the pixels in the pixel region 110a. 
Each of the lead lines 112 is apt to control a row of pixels. If any defect is generated in the lead lines 112 during the fabricating process, the pixels connecting to the lead lines 112 can not display images normally. A displaying image of the liquid crystal display module 100 may show an extraordinary bright line. Specifically, after the color filter substrate 120 and the thin film transistor array substrate 110 are assembled, the defect of the lead lines 112 is further difficult to be repaired. Therefore, the displaying quality of the liquid crystal display module 100 can not be improved.
Besides, in a one drop filling (ODF) process for forming the liquid crystal layer 140, if the sealant 130 is non-uniformly radiated by ultraviolet, the incompletely hardened sealant 130 may contaminate the liquid crystal in the liquid crystal layer 140. For this reason, the black matrix layer 122 on the color filter substrate 120 is slightly shrunk towards the center of the module. However, because of the slight shrink of the black matrix layer 122, an area 170 with light of leakage is formed between the black matrix layer 122 and the sealant 130, wherein the area is corresponding to the inner area R4. In addition, there is no shield between the lead lines 112 within the inner area R4. Hence, light 180 emitted from a back light module may pass through the gaps between the lead lines 112, and light-leakage occurs at the junction between the outer frame 160 and the thin film transistor array substrate 110.
Therefore, in a prior solution, a shield layer, made of a first metal layer (M1) and a second metal layer (M2), is between the lead lines. However, in case of particle contamination or static discharge, shorts occur at the overlap of the shield layer and the metal layer (M1 or M2). If so, a corresponding row of pixels is called a “bright line”, and the module is not qualified.